Plants are breaking ground in the South. Big companies are talking about new designs. President Barack Obama says they can be a key tool in the fight against global warming, and some environmentalists agree.

The exhibit hall at a recent meeting of the American Nuclear Society in San Diego was full of eager industry officials touting everything from 1,000 megawatt plants to machines that allow workers to handle nuclear materials through lead walls.

"There’s a huge renaissance going on,” said Paul Lorenzini, a former utility executive who now heads NuScale Power, an Oregon company developing small reactors. “You don’t have to build the whole plant all at once,” he said, promising a huge change from the way the nation’s 104 commercial nuclear reactors were built decades ago, each custom-designed and built, each one different from the next.

But it’s not happening here in California. New plants using radioactive uranium to make steam to power electric generators are being planned elsewhere in the country, primarily the southeastern U.S., said Ted Quinn, the nuclear society’s former president.

“Others are running faster than we are,” he said.

And it’s not just states like South Carolina, Georgia and Florida, he said. “The rest of the world is way ahead.”

France gets 80 percent of its power from nuclear plants. Japan, Korea and even China — which sits on huge coal deposits — are ordering new plants.

San Diego gets 20 percent of its power from the San Onofre Nuclear Generating Station near Camp Pendleton, but don’t expect a new plant in the region anytime soon.

A 1976 California law says no nuclear plant can be built in the state until the federal government approves a way to deal with high-level nuclear waste — and such approval is unlikely soon.

But it goes beyond that law, said Stephanie Donovan, a spokeswoman for San Diego Gas & Electric, which has battled with critics over projects like its Sunrise Powerlink, a 120-mile line connecting San Diego to the Imperial Valley.

“Given the public opposition to building infrastructure of just about any kind in our service territory, I can’t imagine getting anything through environmental approvals in this region,” she said.

Ed Lyman, a senior scientist with the Union of Concerned Scientists, said wide-scale adoption of new nuclear plants will be a tough sell, even outside California.

The obstacles to new reactors go beyond questions of safety or terrorism concerns. “They’re still incredibly expensive,” he said, and as a result, nuclear power won’t be adopted widely enough to impact global warming.

A new plant the size of San Onofre is expected to cost $8 billion to $12 billion.

And as it cites global warming as a reason to increase the use of nuclear power, the industry is pushing itself as complementary, not competing with sources like solar plants and wind turbines.

“We need everything,” said Joe Colvin, the former president of the Nuclear Energy Institute, a trade group. Many of the arguments against nuclear power focus on safety questions, notably the accident at Three Mile Island in Pennsylvania in 1979 and at Chernobyl in Ukraine in 1986.

Those accidents, however, signaled a change in the industry that has made it much safer, Colvin said.

The meltdown at Three Mile Island “shocked the industry” even though nobody was injured, Colvin said.

Public reaction tainted the industry’s reputation, and companies realized that they had to work together to prevent future accidents. So now, if there’s a problem at one plant that could be repeated elsewhere, everyone knows about it, he said. The industry is also talking about new ways of doing business that could make things safer and cheaper.

Most of the 104 nuclear plants operating in the United States today are custom-built, each one designed pretty much for where it’s located, and each design independently approved.

A few years ago, the industry and the Nuclear Regulatory Commission decided that, to keep costs down, it would come up with standard designs.

The idea is that once a design gets an approval, plants built to its specifications will be easier to license.

Another cost-saving design feature is to cut the complexity, said Ross Ridenoure, chief nuclear officer for Southern California Edison, which runs San Onofre.

“The new plants are simpler than the existing plants: fewer moving parts, fewer pipes, fewer motors,” he said. “If it’s less complex, that translates into it being easier to build.”

Lyman, of the Union of Concerned Scientists, said talk about a nuclear renaissance is for naught.

“Nuclear power still has all the warts it did in the 1970s,” he said.

For Californians, the debate probably won’t make much of a difference.

The state is focused on solar and wind development, and power companies say they will rely on natural gas for the bulk of the power.

Bills dealing with the issue have gone nowhere, said Larry Venus, a spokesman for state Sen. Robert Dutton, a San Bernardino County Republican who proposed including nuclear among the technologies the state can use to fight global warming.

“The word nuclear power, for a number of decades, has made people run in the opposite direction when we should at least be looking at the possibilities,” Venus said. “At this point, legislatively, there does not appear to be any interest in nuclear energy.”